Upload
wilfrid-watts
View
237
Download
2
Embed Size (px)
DESCRIPTION
Temperature & KE The higher the temperature the more kinetic energy the particles in the substance have. The lower the temperature the less kinetic energy the particles in the substance will have.
Citation preview
Ch. 13 - EnergyCh. 13 - Energy
II. Thermal Energy Temperature Thermal Energy Heat Transfer
A. TemperatureA. Temperature
Temperature A measure of the
average kinetic energy of an object’s atoms or molecules
A measure of how hot (or cold) something is.
Temperature & KETemperature & KEThe higher the temperature the
more kinetic energy the particles in the substance have.
The lower the temperature the less kinetic energy the particles in the substance will have.
B. Thermal EnergyB. Thermal EnergyThermal Energy
the sum of the kinetic and potential energy of all the atoms in an object
Thermal energy increases as temperature increases
At constant temperature, thermal energy increases if mass increases.
B. Thermal EnergyB. Thermal EnergyWhich beaker of water has more
thermal energy? B - same temperature, more mass
200 mL
80ºC
A400 mL
80ºC
B
C. Heat TransferC. Heat TransferHeat- the energy transfer
between objects that are at different temperatures.
Energy is always transferred from higher temperature objects to cooler temperature objects.
C. Heat TransferC. Heat TransferWhy does A feel hot and B feel cold?
80ºC
A10ºC
B
Heat flows from A to your hand = hot. Heat flows from your hand to B = cold.
Heat TransferHeat TransferTransformations of energy usually
produce heat!In all Energy transfers, the energy is
spread out uniformly.There are 3 types of energy transfers:
1. Conduction2. Convection3. Radiation
Heat TransferHeat Transfer1. Conduction
The movement of heat through material.
The heat energy is passed from molecule to molecule
Conduction requires direct contact in order for heat to transfer.
Conduction Example: When you grab the handle of a
hot pan on the stove, conduction transfers some of the heat in the pan to your hand resulting in a pain or burn.
Heat TransferHeat Transfer
2. Convection The transfer of
thermal energy by the fluid (gas or liquid) of heated matter particles• Convection
currents transfer heat from warmer to cooler parts of a fluid
Convection Example:A convection oven utilizes a fan to
better move the heated air around the food so that it cooks faster.
Heat Transfer Heat Transfer 3. Radiation
energy transfer by electromagnetic waves
Electromagnetic waves do NOT require a medium in order to travel, therefore, solar radiation can travel through outer space to warm the earth!
Radiant energy can be absorbed, reflected, or transmitted depending upon the properties of the material receiving the energy.
Some forms of radiation (radiant energy) can pass through solids, liquids and gases.
All objects give off radiant energy! Yes, even us!
D. Conductors and InsulatorsD. Conductors and InsulatorsConductor – any material through
which energy can be easily transferred as heat Examples – metals (copper)
Insulator – any material through which energy cannot be easily transferred as heat – a poor conductor
Let’s review…Let’s review…
https://www.youtube.com/watch?feature=player_detailpage&v=7Y3mfAGVn1c